Tommee Tippee is investigating complaints about its Perfect Prep Machine after parents claim to have found mould inside the tubes of the machines.

Parents took to social media this week to complain about the award-winning machines, which make fresh bottles at the right temperature in under two minutes.

The company says ‘a preliminary investigation’ suggests the build-up could be ‘carbon residue and not mould’, but is asking anyone with the problem to send off their machines to be checked in the lab.

One worried mum wrote took to Facebook. She said: “If for one second I ever thought these machines could harm my baby then obviously I would never have used it.

“I can say now after struggling with breastfeeding for months and feeling guilt over formula feeding to start with, I was absolutely devastated to discover the inside of our machine, it is probably the worst I have seen yet.”

In a statement, Tommee Tippee said they are very concerned by the findings and started an immediate investigation.

It said: “Over the weekend, we’ve received comments from parents referring to the internal pipes of their Perfect Prep Machine not being clean. We’re concerned by the findings mentioned in the post and are investigating.

“To help us do this, we’d like parents who’ve found similar build-up to contact us as soon as possible, so we can arrange to have your machine and filter returned to us via Freepost for examination.

Until we’ve investigated, it’s hard to determine the cause, but we’d advise anyone with concerns to contact us via our Careline on 0500 97 98 99.

“We also have several FAQ’s available at www.tommeetippee.co.uk/perfectprepanswers.”